//建议留言
class Advice { 
    String content = ''//内容
    Date createTime = new Date()
    User user

    static constraints = {
        content(size: 1..500,blank: false)
        user(nullable: false)
    }

    static mapping = {
       table 'jiajiao_advice'
    }

    String toString() {
        "${user.realname}"
    }
}
